Enhancement of Open Source Monitoring Tool for Small Footprint Databases

Transcription

1 Enhancement of Open Source Monitoring Tool for Small Footprint Databases Dissertation Submitted in fulfillment of the requirements for the degree of Master of Technology in Computer Science and Engineering Submitted by Sukh Deo Roll No Under the Guidance of Prof. Deepak B. Phatak Department of Computer Science and Engineering Indian Institute of Technology Bombay Powai, Mumbai, India June, 2014

2 Acknowledgement I would like to thank my guide, Prof. Deepak B. Phatak, for the consistent encouragement and guidance throughout the project. Due to his consistent encouragement and right directions, we are able to do this project work. I would like to thank Mr. Nagesh Karmali for his continuous inputs in my work. I would also like to thank, Firuza Aibara, Prashant Kumar Singh, Arun Kumar, and B. Raju for proof reading this report and their valuable feedback. 2

3 Abstract Nowadays, mobile devices are not only used for basic purpose like calls, but also for many different purposes and applications. We can say that mobile devices are siblings of personal computers. Their usage patterns are very different as compared to conventional PCs, as the devices are targeted for general users. They also do have some great features, e.g., light weight and efficiency, but has some drawbacks like small memory and battery issues. Due to the growing number of purposes, people wants to use many applications, but mobile device are able to manage limited number of applications. After literature survey in first stage, we got the result that performance of mobile device depends on management of applications and theire data, i.e., mobile database. There is a need to measure the performance of database and file operation of mobile device, so that we can get information about how much data and operation can perform by the particular device. We already discussed about MobiBench monitoring tool and SQLite database. Now, we will see what are the possible enhancement in Mobibench. Our work starts with some description of Mobibench and SQLite. Going through the existing page replacement technique of SQLite and Android framework, we will test the performance of Akash tablet using Mobibench. We will also discuss the performance testing of Akash tablet after changing the Mobibench.

4 Contents Acknowledgement Introduction Motivation SQLite Mobibench Android Framework SQLite Database Android Frame work Linux Kernel Libraries Android Runtime Application Framework Transaction in SQLite Delete Mode WAL Mode Persist Mode Test Result of Mobibench on Aakash Tablet Overview of Mobibench Measure Tab History Tab Setting Tab Testing Results on Akash Tablet Test Cases for SQLite Test Cases of File System Modification Done in Mobibench Source code Analysis of Mobibench

5 4.2 Modifications Done to Mobibench Database Modification Done to Output View Test Result after Modification of Mobibench on Aakash tablet Testing Result after changes Conclusion and Future Work Conclusion

6 List of Figures 1.1 Smart-phone s Users[1] Android Framework [2] Simple architecture of Android framework Component require for Facebook application Over all view of Mobibench[3] Setting[3] Over all performance IO performance SQLite performance

7 Chapter 1 Introduction 1.1 Motivation Today s mobile devices are multi-functional devices. It provides usage for many applications, both business and consumer purposes. Smart phones and tablets allow people to access Internet for , messages, and web browsing. A business person can install many applications like streamline work-flow, save time, keep data accessible, automate daily tasks, and many others. Consumers can view new goods and their prices on Internet, and many more tasks can be done by mobile devices, i.e., smart phones and tablets. We can work on away from the office using these devices. We can synchronize with our personal computer and can get the updated information. Due to the huge facility and light-weight property of mobile devices, there has been a huge market. People want to use many applications, but these device have some limitations, like small memory and battery backup. There are challenges to manage various applications in these devices. Research can be broadly done in the application and service, device architecture, and operating system area[4]. Traditionally, storage was not viewed as a critical component of these devices, in term of expected performance, but now we got result that performance of mobile device depends on mobile database. Performance of mobile devices are to be to continuously improved to fulfill the desire of users to install and execute more applications. Performance of mobile devices are based on storage performance, e.g., quality of audio/video playback while number of applications are downloaded in back- 4

8 Figure 1.1: Smart-phone s Users[1] ground, storage of web browser history, and browsing speed all of which depends on storage performance. Most mobile devices use embedded Multimedia Card(eMMC), which is based on NAND flash memory. It is also required to use good file systems and I/O schedulers for optimizing the storage performance. In mobile devices, SQLite is used both, as system and application data. Example, SQLite uses to store contacts, message, and bookmarks of the web browser. It stores the entire database in one file. Thus, performance of SQLite depends on storage performance, i.e., how to handle the data and access method within that file. Due to demand of mobile devices in market, there is need to measure its performance, so that we can utilize maximum resources. Based on this motivation, we will discuss embedded database of Android, i.e., SQLite. We will also discuss monitoring tool for Android device, i.e., MobiBench. Specially, we will measure database operation on SQLite and also possible ways to make user friendly of Mobibench. 5

9 1.2 SQLite SQLite is open source database and very light weight databases. If we enable all the features of SQLite in our Apps, size of SQLite Library will be less then 500KB. If we disable optional feature[5], i.e., WAL mode or Delete Mode, the size of SQLite library will be 300KB. It supports the relational database like SQL syntax, transaction, and SQL statement. That why it is available on most of android device. These are overview of SQLite. SQLite Data Types: SQLite supports only three data types TEXT (like String) INTEGER (like int) REAL (like double) SQLiteOpenHelper Class: It is a helper class used to manage database creation and version management. We override the oncreate() and onupgrade() methods in this class. oncreate(): This method is called if the database does not exists. onupgrade(): This method is called if the database version is increased. SQLiteDatabase Class : SQLite Database is the base class for working with a SQLite database. It provides various methods like: Open(), Insert(), Update(), and Close(). ContentValues: ContentValues are used to insert or update database entries. Records are stored as key-value pair in ContentValues. Where : Key represents Column-Id and Value represents data for that Column- Id. 1.3 Mobibench Mobibench allows to measure IO performance and SQLite of Android filesystem[6], and also allows to measure user specified set of tests. It is open source mobile storage performance benchmark tool and provides both characteristics of IOzone and AndroBench. Mobibench is also called workload generator. It analyzes the different application behavior in Android IO and generates the file 6

10 system work load of applications, i.e., file system workload, random and sequential, and synchronous and buffered IO. It is implemented in two versions. First one is shell application and second one is Android application. Both versions are implemented in C language. It uses Java Native Interface(JNI) to run the API, since Java cannot call the App in C directly. Mobibench provides similar environment to smart-phones, to create the workload. 7

11 Chapter 2 Android Framework SQLite Database 2.1 Android Frame work Android is open source and Linux base operating system. It is specially design for mobile device such as tablet and smart phones. Developer only need to develop the application for Android and it will run all the device which has android operating system. Android is powerful operating system that provides many features such as beautiful GUI, storage as SQLite, connectivity, messaging, resizing, multi tasking, and many more. As we are interested in the performance of the android device, first we have to understand the android environment. This will help us to understand the performance bottleneck of Android IO stack. Figure 2.1 shows the overall structure of Android framework. In first part, we have number of application that user really uses, these application directly connected to application framework that will provide required system library of that application. Let us discuss some basic component of Android framework Linux Kernel Linux kernel is bottom up layer, is directly connected to the hardware such as emmc, SD card, and peripheral device. It provides: 8

12 Figure 2.1: Android Framework [2] Process management Memory management Manage network interface Device management such as camera, display, keyboard, and etc Libraries Android developers can use the functionalities provided by these libraries. Function are: Webkit provides web browser SQLite for storage and sharing data for applications SSL provides web security Android Runtime 9

13 This is like Java Virtual Machine, design for optimize for Android Application Framework It help to developer to form Java classes and use of their applications. This is top layer of Android architecture, user can install own application. As we are interested to know the performance bottleneck of mobile device, figure 2.2 shows the way to write data from application to internal memory(emmc) or external memory(sd card). We can conclude that every Android application must use SQLite as database. In mobile device enviroment, we have two main application of mobile device that is highly popular of smart phone, i.e., Facebook and Whatsapp. Facebook uses more then 80% of insert operation[7]. Application SQLite EXT4 Device driver emmc/sd card Figure 2.2: Simple architecture of Android framework Facebook Apps: In first mobile Facebook users were able to update the status only using text message. Later, when smart phone got smarter, they were able to open the Facebook mobile site, i.e. m.facebook.com in mobile browser. But, now Android version of phone has fully features of Facebook as desktop browser provides. Due to continuous increase the efficiency of smart phone, now facebook offer more Apps and add on to Facebook users. Figure 2.3 demonstrate that how Facebook works. Its does not write the data(i.e., chat stuff, images, and information update) in SD card, but use internal memory(emmc). Whatsapp: This is similar to Facebook application, but it specially design for mobile device. 10

14 2.2 Transaction in SQLite In SQLite, there are generally four types of mode that provide different way to transaction that are: Facebook GUI Delete Mode Truncate Mode Persist Mode WAL Mode Mainly android Apps use only two mode(i.e., WAL Mode and Persist Mode) due to performance issue. Let us discuss how transaction mode work when an application wanta to insert the data to SD card or internal memory(emmc). SQLite EXT4 file system emmc as internal memory Figure 2.3: Component require for Facebook application Delete Mode Whenever an Andrpoid application want to insert data or want to sent the data over the network, then first need to write in internal memory of mobile device. There are many insert require before writing in internal memory. Step are following and please refer figure 2.4: SQLite create.db Journal file Write the data in the journal file Call fsync() for flushing into EXT4 file system. EXT4 file system doing same thing in two time, one for erasing and writing in cache memory Call fsync() to flushing data into network 11

15 Delete the journal file In delete mode, we have notice that there are 9 write operation and 2 fsycn() for one insert operation. This is in-efficient and abnormal. We are not using these technique WAL Mode This mode is efficient then all modes, because of least write operation. We can see the figure 2.5. The following step are: Create.db file Write() data Call fsync() Write() call by EXT4 to buffer In this mode 3 write and 1 fsync() are required for one insert. We can say this mode is reasonable of transaction. But this mode is not recoverable Persist Mode This is same as WAL mode, but it provides recoverability feature while failure. It is worst among all mode in term of performance, so it has limited usage.// In this chapter, we have discussed Android framework and how an Android apps use SQLite. We have also discussed the various transaction mode of SQLite and its performance. Next chapter, we will discuss Mobibench and testing on Akash Tablet. 12

16 Chapter 3 Test Result of Mobibench on Aakash Tablet 3.1 Overview of Mobibench Mobibench is also called workload generator. It is implemented in two different versions. First one is shell application and second one is Android application. Both versions are implemented in C language. While running the Android/java version, it uses Java Native Interface(JNI) to run the API, since Java cannot call the Application in C directly. Mobibench provides similar environment to smart-phones, to create the workload and measure ability to execute the number of transaction per second. There are three types of menu button available in Mobibench for users. That are: Measure Tab In mobile device, there are two typs of operation, i.e., database and file operation. Mobibench is able to measure the both types of operations by generating the real kind of load. Figure 3.1 show the available option for user. We have four button that are: ALL: While clicking the ALL button, mobibench generate the two types of operation, i.e., File IO and SQLite simultaneously. It will the give the result as transaction per second. 13

17 File IO: While clicking the File IO button, it generate the only file types of load such as read and write and give the result as KB/s or IOPS. SQLite: While clicking the SQLite button, it generate the query of insert, update, and delete operations and give the result as transaction per second. Performance of SQLite also depends on PRAGRMA options, e.g., synchronous mode or journal mode. It generates three result, i.e., throughput, CPU utilization, and number of context switches. Units of throughput in SQLite operation is transactions per second. Custom: It run only those set of tests that an user choose from the Setting tab. Generally this button customize the test. Figure 3.1: Over all view of Mobibench[3] History Tab History tab keeps the records of previous runs of benchmarks. Whenever we click the record, it will show the result from database. 14

18 3.1.3 Setting Tab Figure 3.2: Setting[3] In figure 3.2 shows setting tab. In this tab we can select various operations of file IO and SQLite transaction. In file IO we have following option: Sequential write Sequential read Random write Random read In Sqlite, we have following options: Insert Update 15

19 Delete It also provides us options to change partition, number of threads in a benchmark, IO size, File size, IO modes, number of transaction, and journal modes of database. Partition: Changes target partition of the device from /data to following partitions. /data: /data partition of internal storage. /sdcard: /sdcard partition of internal storage. /extsdcard: /extsdcard partition of external storage. Number of Threads:Default mode runs in single thread and it allows to increase the number up to 100 threads Custom check box: Using check box, user can select specific tests in a File IO and SQLite benchmarks. File size: Default file size for write and read is 1MB and 32MB, respectively, but we can change according we want. IO Size: Changes the size of IO issued in File IO benchmark. Default size is 4KB. Mode(File IO): Changes synchronization mode for File IO benchmark. Default mode run in O DIRECT mode. As we can change modes available are as follows: Normal: Buffered IO O SYNC: Synchronous IO fsync: SQLite use to flush the data via fsync() system call. O DIRECT:Direct IO mmap: mmaps creates file to virtual address space. Then, the program copies the specified size record, e.g., 4KB, to the mmaped memory region. Upon completing copy of all memory copy, this mode flushes file through msync() to storage device. 16

20 Transaction(SQLite): We can set number of SQL transaction, where default number of transactions is 100. Maximum number of transaction is 10,000. Mode(SQLite) We can change the mode of SQLite. Default mode in SQLite test is FULL. OFF: This mode does not use synchronization mechanism to guarantee that all data is written to the storage device. NORMAL: SQLite uses synchronization mechanism to sync the data to the storage device at certain critical moments, but less often than in FULL mode. FULL: SQLite database is forced to use synchronized via fsync() system call to ensure that all content is safely written to the storage before processing following IO requests. SQLite Journal: We can Change SQLite journal mode. Default mode of SQLite is rollback journal mode. We have other mode also, i.e., WAL, Delete mode, Truncate mode, Persist mode, memory mode, and OFF mode. We can select one among them. 3.2 Testing Results on Akash Tablet We have different version of Aakash tablet. We have to test each version of Aakash tablet with the available specification. In mobibench, we have option to test file IO and SQLite, so we will perform test these option Test Cases for SQLite Test Cases of File System Overall Performance Overall performance means, we are testing performance of file IO and Database IO. 17

21 Test Cases No. of Threads No. of Transactions Journal mode Delete Persist WAL Delete Delete WAL Delete Delete WAL Test cases No. of Threads Filesize(w) Filesize(R) IO Size MB MB KB Mode O Sync O Direct O Sync O Direct O Sync O Direct O Sync O Direct File system performance Figure 3.4 shown the testing result of file system performance. Database Performance Figure 3.5 shown the performance of SQLite transaction, i.e., insert, update, and delete. Aakash3 Aakash4 18

22 Figure 3.3: Over all performance 19

23 Figure 3.4: IO performance 20

24 Figure 3.5: SQLite performance 21

25 Chapter 4 Modification Done in Mobibench 4.1 Source code Analysis of Mobibench I went through the source code of mobibench and I find the possible enhancement can be done that will by make Mobibench user friendly. These changes make user friendly: Currently Mobibench use only one table, i.e. tblmylist (id INTEGER PRIMARY KEY autoincrement, Value TEXT not null, creationdate long). When we talk about the real application, there might be many table for single application. We performed test on Aakash tablet and get the throughput as number in the result, but we can give throughput as a pi chart. I will make easy to user to compare the result usually. We will add some table in Mobibench, so that user can choose any one table to execute the table. 4.2 Modifications Done to Mobibench Database For user friendly we can give the option to user, so that they can upload a query file of Table schema file, insert, delete, and update. When we went through the mobibench code, It was not possible to add these types feature 22

26 because Mobibench has lot of hard coding. If we want to change this feature, then we have to change the many function. But we can to provides many table to user, so that user can choose one table while executing. In Mobibench Setting tab, I gave choose table option, that contains three table, i.e., It contains tblmylist table that is already existed in mo- Default: bibench. Custom: Table schema is: tblmylist (id INTEGER PRIMARY KEY autoincrement, Value1 TEXT not null, Value2 TEXT not null, creationdate long). Customer: Schema is tblmylist (id INTEGER PRIMARY KEY autoincrement, Name TEXT not null, depart TEXT not null, year IN- TEGER, creationdate long). This feature provides user to select the given table. 4.3 Modification Done to Output View I one add one class in Mobibench android code. i.e., graph.class. This will give the result as graph. 23

27 Chapter 5 Test Result after Modification of Mobibench on Aakash tablet 5.1 Testing Result after changes 24

28 Chapter 6 Conclusion and Future Work 6.1 Conclusion 25

29 References [1] Smartphone user in india., URL: accessed: April, 24, 2014]. [2] Android framework. URL: accessed: April, 24, 2014]. [3] Structure of androbenchsetting tab, note=. [4] H. Kim, N. Agrawal, and C. Ungureanu, Revisiting storage for smartphones., TOS, vol. 8, no. 4, p. 14, URL: accessed: Aug, 30, 2013]. [5] Sqlite features., URL: accessed: April, 24, 2014]. [6] J. H. S. L. Sooman Jeong, Kisung Lee and Y. Won, Androstep: Android storage performance analysis too, international/androstep.pdf[last accessed: Sept, 29, 2013]. [7] I/o stack optimization for smartphones. s. jeong, k. lee, s. lee, s. son, and y. won ed. URL: 26